OBD Codes 171 & 174

[delcogod]

I get these codes when the gas tank is between 3/4 and full. It also only happens in the cold weather. (I live near Cleveland) The code reader says both systems are running lean. My manuel has nothing on these codes. Any help would be GREATLY appreciated. Its a 1997 4.0 with auto, 2wd, and 221,000 miles. Its driven at least 75 miles a day for work.

 

[wahlstrom1]

I can almost guarentee you it's a vacuum leak. Bust out the propane torch (unlit) and use it to find the leak while the truck's running. My leak was the lower intake gasket, between it and the fuel rail. It's so common ford has an updated version of the gasket to correct the issue.

-andrew

 

[MAKG]

How does a vacuum leak explain the correlation with fuel level?

It MIGHT be coincidence (it's very easy to get fooled by that), but one solution that explains both is a leak in the fuel pump line, inside the tank.

There are other common lean code causes as well, such as poor PCM grounding, exhaust leaks, etc.

 

[994x4]

I get these codes when the gas tank is between 3/4 and full. It also only happens in the cold weather. (I live near Cleveland) The code reader says both systems are running lean. My manuel has nothing on these codes. Any help would be GREATLY appreciated. Its a 1997 4.0 with auto, 2wd, and 221,000 miles. Its driven at least 75 miles a day for work.

My 99 threw these same codes today. It seams to be running fine. ???
Did you ever find out what caused yours? Thanks

 

[delcogod]

I will try the fuel filter this weekend. Cleared the codes again today, 29 deg and a full tank of gas. Will update, Thanks

 

[mandospd]

My truck is throwing the same codes, 3 times after resetting, I'm going to check for vacuum leaks with propane, I cleaned the MAF and visually inspected everything, the truck is running quite well, but checking for vacuum leaks is the only intelligent next step it seems...if I figure mine out I will re-post....

 

[REDRUM]

i posted this a few weeks ago.
i got the same codes.
truck runs fine though.
haven't done anything about it yet.
could it be plugs or wires?
cause mine are original with 103K miles

 

[mandospd]

http://www.rangerpowersports.com/forum/showthread.php?t=170324&highlight=fuel+rail+gasket